The present invention relates to a high-voltage component and a method for manufacturing a high-voltage component. From German Published Patent Application No. 4108611, a high-voltage component is already known in which laterally arranged partial components are connected in series on a supporting plate. In this context, the partial components are integrated in a thin silicon layer that is applied on the supporting plate, the silicon layer preferably having a thickness of roughly 100 micrometers.
In contrast, the high-voltage component according to the present invention has the advantage of a simple design, since this is due to the fact that a wafer is used which supports itself, no supporting plate is necessary. In this way, a compact, space-saving design results. It should be viewed as a further advantage that through the use of a correspondingly thick wafer, a better current distribution results, in particular a higher current carrying capacity of the high-voltage component, since a greater volume of semiconductor material can contribute to a current flow that is high for a short duration, as is necessary particularly in the case of ignition systems used in motor vehicles. The method according to the present invention has the advantage that it represents a simple method for manufacturing a high-voltage component, dispensing in particular with the use of a supporting plate as well as being able to be packed directly, e.g., by remodeling or by re-casting, without the cumbersome handling of an insulated supporting plate after the etching and passivizing.
It is particularly advantageous that the high-voltage component has planar p-doped wells next to p-doped areas that are configured as separating diffusion areas. In this way, it is possible to realize a base width of an NPN partial transistor that is variable in extensive areas but also spatially homogeneous, for example, if an NPN partial transistor of this type is part of a thyristor that represents the partial component. In particular, spatially defined, homogeneous, small base widths can be used that in a thyristor as component lead to large current amplifications, such as are necessary for the use in the control of an ignition current of an ignition coil in a motor vehicle. In addition, in spite of the use of a thick, self-supporting wafer, it is possible to achieve a high bottom through resistance, so that it becomes possible to trigger the thyristor in a dependable manner and at not excessively high anodic currents. The method of introducing the separating diffusions and also introducing the planar p-doped wells makes possible a simple determination of precise base widths in the use of a thick wafer. This can be explained by the fact that diffusion zones that only protruding into the wafer in a planar fashion can be determined more precisely in their geometric dimensions than, for example, separating diffusion areas.
If the p-well is connected to the p-area configured as a separating diffusion area, the result is a more compact design in the lateral dimensions, and the manufacturing method also becomes simpler.
Providing a resistor area that is in electrical connection with the p-well assures a controlled response to temperature changes of the electrical resistor, which is significant for triggering the high-voltage component.